cleanups, memory savings

src/DirectoryNode.cpp

@@ -470,6 +470,11 @@ void DirectoryNode::buildFlatMP3List(std::vector<std::pair<DirectoryNode *, int>
     }
 }
 
+const size_t DirectoryNode::getNumOfFiles()
+{
+    return subdirectories.size();
+}
+
 DirectoryNode *DirectoryNode::advanceToNextMP3(const String *currentGlobal)
 {
     bool useFirst = false;
@@ -537,7 +542,6 @@ DirectoryNode *DirectoryNode::advanceToNextMP3(const String *currentGlobal)
 void DirectoryNode::streamDirectoryHTML(Print &out) const {
     if (name == "/") {
         out.println(F("<ul>"));
-        delay(0); // yield to WiFi/other tasks
     }
 
     if (name != "/") {
@@ -546,29 +550,24 @@ void DirectoryNode::streamDirectoryHTML(Print &out) const {
         out.print(F("\"><b>"));
         out.print(name);
         out.println(F("</b></li>"));
-        delay(0); // yield periodically while streaming
     }
 
+    delay(0);
+
     for (size_t i = 0; i < mp3Files.size(); i++) {
         out.print(F("<li data-id=\""));
         out.print(ids[i]);
         out.print(F("\">"));
         out.print(mp3Files[i]);
         out.println(F("</li>"));
-        if ((i & 0x0F) == 0) { // yield every ~16 items
-            delay(0);
-        }
     }
 
     for (DirectoryNode* child : subdirectories) {
-        delay(0); // yield before descending
         child->streamDirectoryHTML(out);
-        delay(0); // and after returning
     }
 
     if (name == "/") {
         out.println(F("</ul>"));
-        delay(0);
     }
 }